68 GEOLOGY OF THE LOTHIANS. 



however, that all dip to the N. W. Near Bread Street, the 

 sandstone is crossed vertically by a greenstone dyke about 

 six feet broad. 



Immediately to the west of the city, the hill of Corstor- 

 phin rises with its wooded front, presenting a beautifully 

 undulating surface. This hill is formed by a mass of green- 

 stone reposing upon strata of sandstone, sandstone-flag, 

 bituminous shale, and clay-ironstone, which dip to theN.W. 

 at about 25° ; from the encumbered state of the surface, 

 however, no opportunity is afforded for examining any 

 junctional appearances. The greenstone of Corstorphin is 

 syenitic, and in several places is found to contain minute 

 scales of pinchbeck-brown mica, and iron-pyrites, while 

 prehnite, calcareous spar, amethyst, and common quartz 

 are to be observed in drusy cavities. 



On examining the position of the several rocks entering 

 into the composition of the hills of Arthur's Seat, Salisbury 

 Crags, and the Calton, it will be found that all present a 

 uniform inclination to the W. or N. W. ; and that a simi- 

 lar arrangement exists in the strata forming the bed of the 

 Firth of Forth, is evinced in the island of Inchkeith. 



On proceeding along the coast of Fife, the strata which 

 at Pettycur and Kinghorn have an easterly dip, gradually 

 assume, as we approach Aberdour, a more northerly inclina- 

 tion, till at last they sink completely to the north ; and that 

 this position is also held by those in the adjacent parts of 

 the Firth, is indicated from an examination of the island of 

 Inchcolm. After leaving the strata with the northerly dip, 

 and advancing westward, the exposed rocks acquire pro- 

 gressively a westerly inclination. On the opposite coast of 

 Linlithgowshire, the same arrangement is visible near Queens- 

 ferry, and in the series of sandstone, shale, and greenstone 

 which occurs between the river Almond and Newhaven* 



